DE102009044643A1 - Locking cap with guarantee ring as well as injection mold and process for its production - Google Patents

Abstract

The present invention relates to an injection molding tool for producing a closure cap with an integrally molded guarantee ring. Furthermore, the invention relates to a method for producing such a closure cap and the closure cap as such. The injection molding tool according to the invention is used to produce a closure cap in which a guarantee ring is integrally formed on a closure cap main body via one or more tear-off retaining webs. The injection molding tool initially comprises an outer molded part (02) for forming the outer contour of the closure cap and an inner core part (06) for forming the inner contour of the closure cap. The core part (06) has a section for shaping an inner contour of the closure cap main body and a section for shaping an inner contour of the guarantee ring. In a transition area between the section forming the main body of the closure cap and the section forming the guarantee ring, the core part (06) has one or more hollow shapes (09) for forming the one or more retaining webs. The injection molding tool according to the invention furthermore comprises at least one slide (07) with a receiving surface (08) with which the slide (07) can be pushed onto the one or more hollow molds (09).

Description

The present invention relates to an injection mold for producing a closure cap with an integrally molded guarantee ring. Furthermore, the invention relates to a method for producing such a closure cap and the closure cap as such.

From the prior art, for example from the DE 42 07 996 C2 . WO 93/00270 A1 . DE 36 22 108 A1 and the DE 42 14 151 A1 It is known to form a predetermined tear line for a guarantee ring on a cap by a cutting operation. A disadvantage of this solution is that this requires a further step after pouring the cap.

From the WO 94/14672 A1 It is known to form a guarantee ring by an additional step to a cap warm.

From the prior art, for example from the DE 32 27 510 A1 . DE 32 06 245 A1 and the DE 82 20 978 U1 It is also known to arrange a plastic ring as a guarantee ring on a metal cap. The plastic ring is elaborately designed and has a lower part, which is connected via holding webs with an upper part. The lower part has a smaller diameter than the upper part and the predetermined tear line.

Furthermore, it is known from the prior art, for example from the DE 690 30 586 T2 . DE 196 13 364 C1 . DE 40 16 350 C2 . CH 669 556 A5 and the FR 2 426 617 A1 known to form a predetermined tear line for a guarantee ring on a closure cap in the context of injection molding of the closure cap. In this case, holding webs are formed between an end face of the guarantee ring and an end face of a cap main body. To form the retaining webs, an outer mold part corresponding hollow molds, as in particular in 7 of the CH 669 556 A5 are shown. A disadvantage of this solution is that the cast cap on the predetermined tear line can be removed only with increased effort from the molds for the holding webs. To facilitate this, slides are known for the injection mold, which have the molds for the holding webs, wherein the molds are aligned so that the slide can be removed from the molded cap by a simple push. However, this solution requires elaborately designed molds.

The object of the present invention, starting from the prior art is to provide closure caps with a guarantee ring, the predetermined tear line can be produced with little effort. For this purpose, a suitable injection mold and a method for producing the cap must be specified.

The above object is achieved by an injection mold for producing a closure cap according to the appended claim 1. The object is further achieved by a method for producing a closure cap according to the attached independent claim 9 and by a closure cap according to the attached independent claim 10.

The injection molding tool according to the invention serves to produce a closure cap, in which a guarantee ring is integrally formed on a closure cap main body. The cap main body forms a complete cap except for the guarantee ring. The guarantee ring is integrally formed on the closure cap main body via one or more tearable retaining webs. The one or more tearable support webs form a predetermined tear line and are formed on a lower edge of the cap main body, which edge is not limited to the lowermost edge of the cap main body; For example, when the cap main body has protruding rings for gripping the cap main body. Insofar as the guarantee ring is integrally formed on the closure cap main body via a single tearable holding web, the holding web can be formed by a circumferential band.

The injection mold initially comprises an outer mold part for forming the outer contour of the closure cap. The outer mold part largely defines the outer surface of the cap main body and the guarantee ring, and may be partially or entirely formed by sliders. The injection molding tool according to the invention further comprises an inner core part for forming the inner contour of the closure cap. The core part has a portion for forming an inner contour of the cap main body. Furthermore, the core part has a section for forming an inner contour of the guarantee ring. In a transition region between the closure cap main body forming portion and the guarantee ring forming portion, the core member has one or more molds for forming the one or more holding webs. The one or more cavities are one or more concave structures in the surface of the core member that define at least a substantial portion of the outer shape of the one or more retaining lands. The injection molding tool according to the invention further comprises at least one Slider with a receiving surface, with which the slider is slidable on one or on the plurality of molds. Thus, the one or more slides with their receiving surface on the core part or close to the core part pushed. The receiving surface is shaped such that it can be pushed from the outside to at least a portion of the circumference of the transition region accurately and thereby either contacted the circumference of the core part or maintains a predefined small distance to the core part. In this case, the one or more hollow molds for forming the one or more holding webs remains hollow. The receiving surface forms a conclusion of the one or more molds, which limits these on its radially outer side of the core part. The one or more slides, z. For example, the two or four sliders separate the closure cap main body to be formed from the guarantee ring to be formed so that a space between a lower end surface of the cap main body and an upper end surface of the guarantee ring remains free of material. By contrast, the one or more retaining webs is formed in an interior of the closure cap. The slides can also form the outer mold partially or completely at the same time.

The injection molding tool according to the invention has the advantage over the prior art that the one or more slides have no complicated structures for forming the holding webs. The slides can have as a receiving surface a smooth surface with a hollow-arc-shaped cross-section.

The one or more slides preferably have receiving surfaces, which in their entirety completely surround the transition region of the core part. This ensures complete separation of the cap body to be manufactured from the guarantee ring, so that the guarantee ring is connected to the cap main body exclusively via the one or more holding webs to be formed by the core part.

In the transition region, the core part preferably has a cylinder jacket-shaped surface, as is suitable for closure caps with a circular cross-section, in particular for rotary closures.

In a first preferred embodiment, the core part has exactly one of the hollow shapes. This hollow shape is formed by a peripheral groove extending along the circumference of the core part in its transition region.

In a second preferred embodiment, the core part has a plurality of the hollow molds for forming the holding webs, which are formed as grooves in the transition region, for example in the cylinder jacket-shaped surface. The longitudinal directions of the grooves are preferably aligned parallel to an axis of the core part.

In order to be able to receive the cylinder jacket-shaped surface of the transition region of the core part, the receiving surfaces of the one or more slides preferably each have a hollow circular arc-shaped cross section. The diameter of the hollow circular arc-shaped cross-section is matched to the diameter of the cylinder jacket-shaped surface of the core part, so that the transition region of the core part can be positively received by the receiving surfaces of the one or more slides. Apart from the grooves, the transition area is contacted in full by the receiving surfaces of the one or more slides. The receiving surfaces cover the grooves, so that tubular-like molds are formed to form the retaining webs.

The injection molding tool according to the invention preferably has two of the slides whose receiving surfaces each have a hollow semicircular arc-shaped cross section. The two slides can each take up half the circumference of the transition region of the core part and can be pushed effortlessly from two opposite sides onto the core part in order to prepare the injection molding tool according to the invention for casting a closure cap.

The receiving surfaces preferably each have the hollow shape of a Zylindermantelkalotte to accommodate the cylinder jacket-shaped surface of the transition region of the core part can be flat.

The grooves for forming the retaining webs can have any profile. Preferably, the grooves each have the hollow shape of a half-cylinder, which can be easily removed from the grooves to be molded holding webs. In a further preferred embodiment, the grooves each have a trapezoidal cross-sectional area, wherein the cross-sectional area is smaller at the transition to the sealing cap main body forming portion than at the transition to the guarantee ring forming portion. For example, the cross-sectional area may be formed to become progressively smaller in the direction of transition to the cap body forming portion, for example, by making the bases of the trapezoidal shape of the cross-sectional area toward the transition to the Cap body main body forming section become linear shorter. In this embodiment, it is ensured that the holding webs to be formed of the closure cap to be produced with the injection mold break when first opening the cap at the transition to the cap main body, so that the holding webs remain on the guarantee ring, where they have a lower risk of injury. In contrast to solutions from the prior art, in which the predetermined tear line is created by cutting, longer holding webs can be realized by means of the solution according to the invention, for example to guarantee a low breaking strength.

The cylinder jacket-shaped surface of the transition region of the core part is preferably not limited to the transition region. This is followed in the direction of the closure cap main body forming portion of a cylinder jacket-shaped surface of the same diameter. In the same way adjoins the transition region in the direction of the guarantee ring forming portion of a cylinder jacket-shaped surface of the same diameter. Such a design ensures easy removal of the cap to be manufactured. Furthermore, it is ensured that the one or more holding webs to be formed are located completely inside the closure cap.

The method according to the invention serves to produce a closure cap with a guarantee ring integrally formed on one lower edge of a closure cap main body via one or more tearable holding webs. To carry out the method, first of all, for example, the above-described injection molding tool according to the invention has to be provided. For this purpose, the injection mold for the injection molding is to be prepared; For example, the one or more slides to push on the transition region of the core part. The injection mold is to be filled with a liquid plastic, for example with a heated liquefied plastic, which is introduced at an elevated pressure in the injection mold. Subsequently, the plastic hardens, for example by cooling. The cured plastic forms inside the injection mold from the produced cap. Afterwards, open the injection mold and remove the cap.

A particular advantage of the method according to the invention is that the production of the closure cap, in particular the formation of a predetermined tear line requires no further work steps, such as a cutting operation.

The closure cap according to the invention has a guarantee ring integrally formed on one lower edge of a closure cap main body via one or more tearable holding webs. The closure cap according to the invention is characterized in that it can be produced, for example, by the method according to the invention described above. Consequently, after production, it has a clearance between a lower end surface of the cap main body and an upper end surface of the guarantee ring which has not been inserted into a molded cap blank by cutting or similar machining. Rather, these faces have surfaces as they are in the result of injection molding. At the same time, the one or more holding webs are arranged inside the closure cap and does not protrude or only slightly into the space between the end faces of the closure cap main body and the guarantee ring.

Further advantages, details and developments of the invention will become apparent from the following description of a preferred embodiment of the injection mold according to the invention and several preferred embodiments of the closure cap according to the invention, with reference to the drawing. Show it:

1 a sectional view of a preferred embodiment of an injection mold according to the invention in an open state;

2 : this in 1 shown injection mold in a closed state;

3 : this in 2 shown injection mold in a partially sectioned view;

4 : a perspective view of an internal structure of the in 1 shown injection mold;

5 : another sectional view of the in 1 shown injection mold;

6 a first preferred embodiment of a closure cap according to the invention in a sectional view;

7 a second preferred embodiment of the closure cap according to the invention in a sectional view; and

8th A third preferred embodiment of the closure cap according to the invention in a sectional view.

1 shows a sectional view of a preferred embodiment of an injection mold according to the invention for producing a closure cap in an open state. The injection molding tool according to the invention initially comprises a tool frame 01 in which, inter alia, an outer mold part 02 is enclosed. The outer molding 02 serves to shape the outer contour of the cap to be produced. In the illustration shown is a cylindrical mold 03 to recognize the formation of a cap main body. The cylindrical mold 03 has a profile 04 to form a gripping surface on the surface of the cap to be produced.

The injection mold further comprises an inner core part 06 for forming the inner contour of the closure cap to be produced. The inner core part 06 has substantially the shape of a cylinder and has inter alia a structure (shown in FIG 5 ) for forming a thread of the cap to be produced.

The illustrated cross-section of the injection molding tool according to the invention is arranged in a plane in which a desired tear line of the closure cap is to be formed. In this plane, the injection molding tool according to the invention has two slides 07 on which within the tool frame 01 are arranged displaceably. In particular, the two slides can be 07 on the core part 06 push, causing the two slides 07 with recording surfaces 08 the core part 06 to contact. The recording surfaces 08 each have a hollow semi-circular cross-section (not to scale representation) to the cylindrical core part 06 completely enclose circumferentially. The recording surfaces 08 preferably have no structure o. Ä., So that they are inexpensive to produce.

The core part 06 points in the plane of the two slides 07 in its cylinder jacket-shaped surface circumferentially equally distributed grooves 09 on. The grooves have a semicircular cross section, so that they form the hollow shapes of a half-cylinder. The grooves 09 extend in a direction which is parallel to a central axis of the cylindrical shape of the core part 06 is aligned.

2 shows that in 1 illustrated injection mold in a closed state. In the closed state are the two slides 07 contacting the core part 06 pushed, so the receiving surfaces 08 the core part 06 in the plane of the two slides 07 enclose completely circumferentially. The cylinder jacket-shaped surface of the core part 06 gets in the plane of the two sliders 07 completely from the two receiving surfaces 08 contacted. This will be the grooves 09 covered, so that tubes are formed with a semicircular cross-section.

3 shows a further cross section of the in 2 shown injection mold. The core part 06 is shown partially cut to several of the grooves 09 to be recognized. This also shows that the grooves 09 starting from the contact surface between the receiving surfaces 08 and the core part 06 in the core part 06 do not extend and just into the outer molding 02 ,

4 shows an inner structure of in 1 shown injection mold in a perspective view. In particular, the mold formed in the injection mold is shown, which includes a hollow mold 11 for the guarantee ring, the grooves 09 and the profile 04 includes. Furthermore, the two slides 07 and their arrangement relative to the mold formed in the injection mold shown.

5 shows a further cross section of the in 1 shown injection mold. The cross section shown is arranged in a plane in which the axis of symmetry of the core part 06 lies. Again, the hollow mold present in the injection mold is shown. To form the guarantee ring is between the outer molding 02 and the core part 06 the hollow cylindrical mold 11 educated. Furthermore, in this illustration, a mold 12 for a thread inside the cap shown. Also is a mold 13 recognizable for an annular sealing lip inside the cap. The mold forming the closure cap main body 03 and the guarantee ring forming hollow mold 11 apart from the mold 12 for the thread on a same inside and a same outside diameter. Also features the core part 06 in the area of the grooves 09 apart from the grooves 09 , a cylinder-shell-shaped surface whose diameter is the diameter of the core part 06 in the area of the mold 11 for the guarantee ring and in the area of the mold 03 for the cap main body.

In the illustrated embodiment of the injection molding tool, an injection point (not shown) is attached to the inside of the mold. The hollow mold for forming the closure cap can also be arranged rotated by 180 ° relative to the illustrated arrangement with respect to the injection mold, so that the injection point can be attached to the mold from the outside.

6 shows a first preferred embodiment of a cap according to the invention in a sectional view. The closure cap initially comprises a closure cap main body 16 to which a guarantee ring 17 is integrally formed. The cap main body 16 has substantially the shape of a hollow cylinder closed on one side, on the inside of which a thread 18 and a sealing lip 19 are formed. The guarantee ring 17 Also has the shape of a hollow cylinder, wherein the diameter of the hollow cylindrical shapes of the cap body 16 and the guarantee ring 17 same.

The guarantee ring 17 is over a single holding bridge in the form of a circulating band 21 integral with the cap main body 16 formed. The circulating band 21 Forms a ring whose transition to the cap main body 16 or to the guarantee ring 17 acts as a predetermined tear line. The outer diameter of the circulating belt 21 formed ring is as large as the inner diameter of the hollow cylindrical shapes of the cap body 16 and the guarantee ring 17 , Thus, the circulating band 21 arranged inside the cap. Consequently, the gap is between a lower end face of the cap main body 16 and an upper end surface of the guarantee ring 17 free of material.

The ribbon 21 points at the transitions to the cap main body 16 and to the guarantee ring 17 one circumferential bevel each 22 ensuring that the transitions have a narrow cross section and therefore the guarantee ring 17 easily peeled off. Incidentally, the tape points 21 both in the direction of the circumference of its hollow cylindrical shape and in the direction of the axis of symmetry of its hollow cylindrical shape to a constant material thickness.

The guarantee ring 17 is about the circulating band 21 as the only holding bridge on the cap main body 16 whereas in the 1 to 5 shown injection molding tool for producing a closure cap is provided, in which a plurality of retaining webs are formed.

7 shows a second preferred embodiment of the closure cap according to the invention in a sectional view. This embodiment is initially similar to the one in FIG 6 shown embodiment. One difference is that the band 21 in the direction of the axis of symmetry of its hollow cylindrical shape, in particular in the direction of the closure cap main body 16 has a decreasing material thickness, whereby the predetermined tear line at the transition to the cap main body 16 is defined.

8th shows a third preferred embodiment of the closure cap according to the invention in a sectional view. This embodiment is initially similar to the one in FIG 6 shown embodiment. One difference is that the band 21 only at the transition to the cap main body 16 the bevel 22 has, whereby the predetermined tear line is defined at this transition.

LIST OF REFERENCE NUMBERS

01

tool frame

02

Outer molding

03

Mold for closure cap main body

04

profile

05

-

06

core part

07

pusher

08

receiving surfaces

09

groove

10

-

11

Mold for warranty ring

12

Mold for thread

13

Mold for sealing lip

14

-

15

-

16

Cap main body

17

tamper ring

18

thread

19

sealing lip

20

-

21

circulating band

22

bevel

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4207996 C2 [0002]
• WO 93/00270 A1 [0002]
• DE 3622108 A1 [0002]
• DE 4214151 A1 [0002]
• WO 94/14672 A1 [0003]
• DE 3227510 A1 [0004]
• DE 3206245 A1 [0004]
• DE 8220978 U1 [0004]
• DE 69030586 T2 [0005]
• DE 19613364 C1 [0005]
• DE 4016350 C2 [0005]
• CH 669556 A5 [0005, 0005]
• FR 2426617 A1 [0005]

Claims (12)

An injection molding tool for producing a closure cap having a lower edge of a closure cap main body ( 16 ) via one or more breakable retaining webs ( 21 ) integrally molded guarantee ring ( 17 ), comprising: - an outer molding ( 02 ) to form the outer contour of the cap; - an inner core part ( 06 ) for forming the inner contour of the closure cap, which in a transition region between a closure cap main body ( 16 ) forming section and a guarantee ring ( 17 ) forming section one or more molds ( 09 ) for forming the one or more retaining webs ( 21 ) having; and at least one slider ( 07 ) with a receiving surface ( 08 ), with which the slider ( 07 ) on the one or more molds ( 09 ) is slidable. Injection mold according to claim 1, characterized in that the inner core part ( 06 ) has in the transition region exactly one of the molds, which is formed by a along the circumference of the core part ( 06 ) is formed in the transition region extending circumferential groove. Injection mold according to claim 1, characterized in that the inner core part ( 06 ) in the transition region, several of the hollow molds ( 09 ), and that the core part ( 06 ) in the transition region has a cylinder jacket-shaped surface, in which the molds forming grooves ( 09 ), wherein the one or more slides ( 07 ) with their receiving surfaces ( 08 ) on the core part ( 06 ) is slidably contacting the transition region. Injection mold according to claim 3, characterized in that the receiving surfaces ( 08 ) of the one or more slides ( 07 ) each have a hollow arc-shaped cross-section, wherein the receiving surfaces ( 08 ) in one the core part ( 06 ) contacting state receiving the cylinder jacket surface and the grooves ( 09 ) are arranged overlapping. Injection mold according to claim 4, characterized in that it has two slides ( 07 ), wherein the receiving surfaces ( 08 ) each have a hollow semicircular arc-shaped cross section. Injection mold according to one of claims 3 to 5, characterized in that the grooves ( 09 ) each have the hollow shape of a half-cylinder. Injection mold according to one of claims 3 to 5, characterized in that the grooves each have a trapezoidal cross-sectional area, wherein the cross-sectional area at the transition to the cap body ( 16 ) forming section smaller than at the transition to the guarantee ring ( 17 ) forming section is. Injection molding tool according to one of claims 1 to 7, characterized in that the cylinder head-shaped surface of the transition region in the direction of the closure cap main body ( 16 ) forming section and in the direction of the guarantee ring ( 17 ) forming section in each case followed by a cylinder jacket-shaped surface of the same diameter. Method for producing a closure cap, comprising the following steps: Providing an injection molding tool, preferably according to one of Claims 1 to 8, which has a shape for producing the closure cap with a closure at a lower edge of a closure cap main body ( 16 ) via one or more breakable retaining webs ( 21 ) integrally molded guarantee ring ( 17 ) trains; - filling the injection mold with a liquid plastic; - curing the plastic; - Opening the injection mold; and - removal of the cap. Closure cap with a at a lower edge of a cap main body ( 16 ) via one or more breakable retaining webs ( 21 ) integrally molded guarantee ring ( 17 ), wherein a free space between a lower end surface of the cap main body ( 16 ) and an upper end face of the guarantee ring ( 17 ), characterized in that the free space is not provided by cutting or similar machining in the cap main body (FIG. 16 ) has been introduced so that this lower end surface of the cap main body ( 16 ) and this upper end face of the guarantee ring ( 17 ) each have surfaces as they are present as a result of injection molding of the cap. Cap according to claim 10, characterized in that the one or more retaining webs ( 21 ) are arranged inside the closure cap and not or only slightly in the space between the end faces of the closure cap main body ( 16 ) and the guarantee ring ( 17 protrude). Cap according to claim 10 or 11, producible by a method according to claim 9.

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